enh: fixed #4302 (#4315)

Amended recommendation by @keewis

Author: zerothi

setup.cfg

@@ -69,7 +69,7 @@ classifiers =
     Topic :: Scientific/Engineering
 
 [options]
-packages = xarray
+packages = find:
 zip_safe = False  # https://mypy.readthedocs.io/en/latest/installed_packages.html
 include_package_data = True
 python_requires = >=3.6
@@ -197,4 +197,4 @@ ignore_errors = True
 test = pytest
 
 [pytest-watch]
-nobeep = True
+nobeep = True